Resistive-type non-volatile memories (NVMs), such as phase change random access memories (PCRAMs) and resistive RAMs (RRAMs), employ memory elements having different stable resistive states. Such resistive elements enable data corresponding to the different resistive states to be stored. For PCRAMs, the memory element switches between the amorphous and crystalline phases. Switching between the two phases is achieved by heating the memory element using a heater. As for RRAMs, the memory element switches between the insulating and conducting phases by creating or destroying conductive filaments. Unlike flash memories, NVMs using resistive elements do not need high voltages to program the cells. This results in lower power consumption compared to flash memories as well as avoiding the need for high voltage masks for forming high voltage transistors in manufacturing such devices.
However, conventional resistive type memories have drawbacks. For example, conventional PCRAMs and RRAMs have large memory elements. For example, in PCRAMs, this leads to a large heater-to-memory element contact area which results in inefficient heating to switch the phase of the memory element. This increases power consumption. As for RRAMs, a large memory element leads to a large number of conductive filament current paths formed. This results in large resistance distribution, negatively impacting resistance state margins.
This disclosure is directed to resistive type memories with small memory elements with improved performance.